Movement patterns and space use of a large, aquatic turtle, with a comparison of GPS, VHF, and acoustic transmitters

Abstract

The Central American river turtle Dermatemys mawii is a large, strictly aquatic turtle that is Critically Endangered due to overharvesting, and there are many key knowledge gaps about its ecology, including its movement patterns and space use (home range). Due to its secretive and entirely aquatic nature, D. mawii is difficult to study. Therefore, we tested 3 types of transmitter (GPS, radio [VHF], and acoustic) and used them to study D. mawii space use and movements. Both VHF and GPS transmitters had little or no utility for this species. Acoustic transmitters were, however, highly effective, and we used them to track 19 D. mawii. On average, individuals traveled 446 m d–1, but 1 individual moved 5.24 km in under 24 h. Turtles moved significantly more per day (mean = 593.2 m) after the first flooding event of the year than they did before the flooding (184.3 m d–1). Additionally, when the creek flooded its banks, turtles moved onto the floodplain to forage. Individuals used a large section of the creek, with a mean ± SD space use of 8.07 ± 4.69 km (range:1.74–21.38 km) along the creek, suggesting that large areas need to be protected to conserve this species. We observed high rates of illegal harvesting, with between 10.5 and 21.1 % of our individuals poached over a 5 mo period. Such a high harvest rate is unsustainable, and we stress the urgent need for increased conservation efforts.

Department(s)

Biology

Document Type

Article

DOI

10.3354/esr01442

Keywords

Chelonian, Conservation, Dermatemys mawii, Ecology, Flooding, Home range, Poaching, Space use

Publication Date

1-1-2025

Journal Title

Endangered Species Research

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